1. Field of the Invention
The present invention relates to an isolator system interposed between the engine and passenger compartments of an automotive vehicle so as to reduce the transmission of unwanted noise and vibration from the engine compartment and into the passenger compartment.
2. Disclosure Information
As luxury passenger cars have become increasingly quieter within the passenger compartment, or cabin, it has become necessary to develop new structures, methods and materials for isolating noise vibration and harshness (NVH) originating from within the engine compartment of the vehicle. In response to the need to reduce structure borne noise by limiting paths for the transmission of noise between the engine compartment and the passenger compartment, vehicle manufacturers have gravitated to solutions which, although effective, are quite costly. Thus, for example, it is known to use a second metallic dash panel in combination with a first metallic panel so as to decouple the passenger compartment from the engine compartment. Unfortunately, this is a very expensive solution to the problem. Moreover, the problem is exacerbated when the vehicle is of the cab forward design in which the engine compartment is in fact tucked under the leading edge of the windshield. This detrimental result arises from the fact that automotive bodies having cab forward designs have cowl structures with both vertical and horizontal surfaces which function to radiate noise into the vehicle passenger compartment.
A system according to the present invention provides a cost effective means for reducing structure borne noise as well as airborne noise transmitted from the engine compartment to the passenger compartment or a vehicle.
A passenger compartment isolator system interposed between the engine compartment and passenger compartment of an automotive vehicle includes a dash panel having a first portion extending generally vertically from a toeboard area of the passenger compartment floor to a position rearward of the leading edge of the vehicle""s windshield, and a second portion extending generally horizontally from the upper end of said first portion to a position underlying the leading edge of the windshield. An isolator panel affixed to the engine compartment side of the dash panel has a first portion applied to the generally vertical portion of the dash panel and a second portion applied to and depending from a generally horizontal portion of the dash panel.
An isolator panel according to one aspect of the present invention preferably comprises a unitary composite of elastomer bonded to a relatively more rigid plastics material. More specifically, the isolator panel may comprise a composite of cast foam bonded to a molded sheet such as thermoplastic olefin. In such case, the isolator panel will be positioned such that the cast foam is interposed between the dash panel and the molded sheet. The isolator panel may further comprise an air intake duct extending generally toward the engine compartment and away from the passenger compartment with the duct having an aperture in an upper surface for conducting air from a cowl area of the vehicle and into the passenger compartment.
It is an advantage of the present invention that an isolator system according to this invention will greatly reduce the ingress of NVH from the engine compartment and into the passenger compartment of an engine-equipped vehicle.
Another advantage of the present invention is that an isolator system according to this invention will produce superior NVH reduction in the passenger compartment without the high cost attendant a separate steel or other metallic panel applied in addition to the dash panel.
Other advantages, as well as objects and features of the present invention, will become apparent to the reader of this specification.